Movement and Muscle Contraction in Organisms
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Questions and Answers

What feature helps marine mammals reduce drag while swimming?

  • Hair-covered body
  • Large size
  • Hind limbs
  • Smooth skin (correct)

Marine mammals primarily use their front legs for steering while swimming.

False (B)

What are flukes used for in marine mammals?

To increase thrust when the tail is moved up and down.

Marine mammals' bodies are shaped to be widest near the ______ to minimize resistance.

<p>front</p> Signup and view all the answers

Match the following features of marine mammals with their functions:

<p>Blubber = Provides buoyancy Dorsal fin = Prevents rolling Flippers = Steering Flukes = Increases thrust</p> Signup and view all the answers

Which component of synovial joints helps to prevent friction and absorb shocks?

<p>Cartilage (C)</p> Signup and view all the answers

What is the primary mechanism by which myosin pulls actin during contraction?

<p>Cross-bridge cycling (C)</p> Signup and view all the answers

Tendons attach muscle to muscle.

<p>False (B)</p> Signup and view all the answers

What is the function of ligaments in synovial joints?

<p>To prevent dislocation of the joint.</p> Signup and view all the answers

The dark band of the sarcomere shortens during muscle contraction.

<p>False (B)</p> Signup and view all the answers

Name the elastic protein that stores potential energy during muscle relaxation.

<p>titin</p> Signup and view all the answers

The device used to measure the range of motion at a joint is called a __________.

<p>goniometer</p> Signup and view all the answers

Match the types of joints with their range of motion:

<p>Hinge joint = Flexion and extension Ball-and-socket joint = Movement in three planes Pivot joint = Rotation Saddle joint = Bending and straightening in two planes</p> Signup and view all the answers

During muscle relaxation, potential energy is stored by _____.

<p>titin</p> Signup and view all the answers

Which part of a synovial joint secretes synovial fluid?

<p>Joint capsule (C)</p> Signup and view all the answers

What is the primary function of muscle contraction in organisms?

<p>To enable movement (C)</p> Signup and view all the answers

Match the following components with their functions:

<p>Myosin = Forms cross-bridges with actin Actin = Thin filaments in muscle contraction Titin = Stores potential energy and prevents overstretching Z-disc = Anchors the actin filaments</p> Signup and view all the answers

What role do antagonist muscles play during muscle lengthening?

<p>They provide energy to relax another muscle (D)</p> Signup and view all the answers

The range of motion in hinge joints is limited to one plane.

<p>True (A)</p> Signup and view all the answers

All organisms are motile and can move from one location to another.

<p>False (B)</p> Signup and view all the answers

How does synovial fluid contribute to joint health?

<p>It lubricates the joint, reducing friction during movement.</p> Signup and view all the answers

Myosin filaments have multiple heads, allowing them to exert more force during contraction.

<p>True (A)</p> Signup and view all the answers

What type of organism is a bar-tailed godwit, and how far does it migrate?

<p>Motile organism, migrates 10,400 km</p> Signup and view all the answers

The two types of protein filaments found in sarcomeres are _______ and _______.

<p>actin, myosin</p> Signup and view all the answers

How much do myosin heads pull actin toward the center of the sarcomere during each cycle?

<p>about 10 nm</p> Signup and view all the answers

Match the following terms with their correct descriptions:

<p>Motile organisms = Can move from one place to another Sessile organisms = Remain in a fixed position Peristalsis = Internal movement in the gut Coral polyps = Example of a sessile organism</p> Signup and view all the answers

What do thin actin filaments overlap with in a sarcomere?

<p>Myosin filaments (D)</p> Signup and view all the answers

The dark band in a sarcomere contains actin but not myosin filaments.

<p>False (B)</p> Signup and view all the answers

What adaptions do motile organisms like bar-tailed godwits have for locomotion?

<p>Wings for flight</p> Signup and view all the answers

What is a motor unit?

<p>A motor neuron and all the muscle fibres it stimulates (A)</p> Signup and view all the answers

Arthropods have endoskeletons made of bony structures.

<p>False (B)</p> Signup and view all the answers

What is an example of how honey bees forage for food?

<p>Bees fly from flower to flower searching for nectar and pollen. (B)</p> Signup and view all the answers

Salmon migrate to fresh water during their adult life.

<p>True (A)</p> Signup and view all the answers

What role does the fulcrum play in a lever system?

<p>It acts as the pivot point.</p> Signup and view all the answers

The neurotransmitter used at the neuromuscular junction is __________.

<p>acetylcholine</p> Signup and view all the answers

What do male bees do to find a mate?

<p>Male bees fly at a height of 10-40 m and mate with a virgin queen.</p> Signup and view all the answers

The ______ muscles contract to move the ribcage up and out during inhalation.

<p>external intercostal</p> Signup and view all the answers

Match the following terms with their definitions:

<p>Origin = Fixed attachment point of the muscle Insertion = Moving attachment point of the muscle Effort = Force applied to a lever Resultant Force = Outcome force produced by a lever</p> Signup and view all the answers

How do internal intercostal muscles aid in exhalation?

<p>They pull the ribs down and in. (B)</p> Signup and view all the answers

Which type of skeleton do vertebrates have?

<p>Endoskeleton (D)</p> Signup and view all the answers

Muscle contraction at the origin causes movement.

<p>False (B)</p> Signup and view all the answers

Match the following actions with their corresponding muscle type or animal example:

<p>Foraging for food = Honey bees Mating behavior = Male salmon Escaping from predators = Salmon Ribcage movement = Intercostal muscles</p> Signup and view all the answers

Muscles facilitate movement by providing an anchorage to the __________.

<p>skeleton</p> Signup and view all the answers

Both external and internal intercostal muscles work together to cause inhalation.

<p>False (B)</p> Signup and view all the answers

What is the main purpose of the contraction of external intercostal muscles?

<p>To increase the volume of the thorax and draw air into the lungs.</p> Signup and view all the answers

Flashcards

Motile Organisms

Organisms that can move their entire body from one place to another.

Sessile Organisms

Organisms that permanently stay in one place.

Locomotion

The movement of an organism from one place to another.

Sarcomere

The functional unit of a muscle fiber, responsible for muscle contraction.

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Z-disc

Structure that connects the ends of actin filaments and separates adjacent sarcomeres.

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Actin Filaments

Thin protein filaments that make up part of the sarcomere, responsible for muscle contraction.

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Myosin Filaments

Thick protein filaments that make up part of the sarcomere, responsible for muscle contraction.

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Muscle Contraction

The process of shortening a muscle, caused by the sliding of actin and myosin filaments.

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What is the function of a dorsal fin in marine mammals?

The dorsal fin is a vertical fin on the back of marine mammals that helps to provide stability by preventing rolling.

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How do marine mammals achieve streamlined bodies?

Marine mammals have a streamlined body shape: they're widest near the front and taper towards the rear. This reduces drag, making swimming easier.

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What is the purpose of blubber in marine mammals?

Blubber is a thick layer of fat that marine mammals have. It provides buoyancy, which helps them float in water, and insulation, keeping them warm.

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Why do marine mammals need adaptations for periodic breathing?

Marine mammals need to come up for air regularly, so they have adaptations to close their airways during dives. This prevents them from getting water in their lungs.

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What is the role of flippers in marine mammals?

Flippers are modified front legs that help marine mammals steer and move through the water. They're much more efficient than legs for swimming.

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Synovial joint

A type of joint that allows for movement and is filled with synovial fluid for lubrication. It's made up of bones, muscles, tendons, cartilage, ligaments, and a joint capsule.

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Cartilage in synovial joints

A smooth, tough tissue that covers bone ends in synovial joints. It reduces friction and absorbs shocks to prevent bone damage.

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Synovial fluid

A lubricating fluid found inside synovial joints. It reduces friction between bones during movement and allows smooth gliding.

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Ligaments in synovial joints

Tough, fibrous cords of tissue connecting bones in synovial joints. They help to stabilize the joint and prevent dislocation.

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Range of motion (ROM)

The extent to which a joint can move. Different joints allow for different ranges of motion.

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Goniometer

A tool used to measure the angles of movement at a joint (ROM). It helps determine the degree of movement possible.

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Hinge joint

A type of synovial joint that allows movement in only one plane, like bending and straightening (flexion and extension).

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Ball-and-socket joint

A type of synovial joint that allows movement in three planes: protraction/retraction, abduction/adduction, and rotation.

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What is the purpose of intercostal muscles?

Intercostal muscles are responsible for the movement of the ribcage, which is essential for breathing. They help to increase the volume of the chest cavity during inhalation and decrease it during exhalation.

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What is a motor unit?

A motor unit is a single motor neuron and all the muscle fibers it innervates. It allows for coordinated muscle contraction by stimulating multiple fibers simultaneously.

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What are the two layers of intercostal muscles?

There are two layers of intercostal muscles: external intercostal muscles and internal intercostal muscles. They are arranged in opposite directions and work antagonistically, meaning one contracts while the other relaxes.

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What is the role of acetylcholine in muscle contraction?

Acetylcholine is a neurotransmitter released at the neuromuscular junction, the synapse between a motor neuron and a muscle fiber. It triggers the muscle fiber to contract.

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How does the external intercostal muscle affect the ribcage?

When external intercostal muscles contract, they pull the ribcage up and out, increasing the volume of the thorax. This creates a pressure difference, causing air to be drawn into the lungs (inhalation).

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What is an exoskeleton?

An exoskeleton is a tough, external body covering that provides support and protection. It is found in animals like insects, crustaceans, and spiders.

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How does the internal intercostal muscle affect the ribcage?

When internal intercostal muscles contract, they pull the ribcage down and in, decreasing the volume of the thorax. This forces air out of the lungs (exhalation).

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What is an endoskeleton?

An endoskeleton is an internal framework of bones that provides support and protection. It is found in vertebrates like humans, fish, and birds.

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Sarcomere: What is it?

The basic unit of a muscle fiber, responsible for muscle contraction. It consists of overlapping actin (thin) and myosin (thick) filaments.

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What happens to the muscles during inhalation?

During inhalation, the external intercostal muscles contract, pulling the ribcage up and out. At the same time, the internal intercostal muscles relax.

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What is the difference between the origin and insertion of a muscle?

The origin of a muscle is the fixed attachment point, while the insertion is the attachment point that moves when the muscle contracts. The origin is typically stationary, and the insertion moves.

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What are the light bands in a sarcomere?

The light bands, also known as I-bands, are regions of a sarcomere containing only actin filaments. They appear lighter because they are less dense than the dark bands.

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How do skeletons facilitate movement (levers)?

Bones act as levers, changing the size and direction of force applied by muscles. The fulcrum is the joint, the effort is muscle contraction, and the resultant force moves the bone.

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What happens to the muscles during exhalation?

During exhalation, the internal intercostal muscles contract, pulling the ribcage down and in. The external intercostal muscles relax.

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What are the dark bands in a sarcomere?

The dark bands, also known as A-bands, are regions of a sarcomere where both actin and myosin filaments overlap. They appear darker because they are denser than the light bands.

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What is the relationship between limb length and movement speed/force?

Longer limbs with the insertion far from the fulcrum favor speed over force. Shorter limbs with the insertion close to the fulcrum favor force over speed.

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What are the roles of antagonistic muscles in breathing?

Antagonistic muscles, like the external and internal intercostal muscles, work in opposition to each other. This allows for controlled and efficient movement of the ribcage, which is essential for breathing.

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What is the role of titin molecules in breathing?

When one layer of intercostal muscles relaxes, titin molecules in the sarcomeres of those muscles are stretched by the contracting muscle. This stores potential energy which can be quickly released to assist with the next contraction.

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What is articulation?

Articulation refers to movement at a joint, allowing bones to move relative to each other.

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What is the Z-disc?

The Z-disc is a protein structure that anchors the actin filaments of a sarcomere. It marks the boundary between two adjacent sarcomeres.

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How does a sarcomere contract?

The actin filaments slide past the myosin filaments, pulling the Z-discs closer together, resulting in a shortening of the sarcomere. The dark band does not change in length, while the light band shortens.

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What is a cross-bridge?

A temporary connection formed between the myosin head and an actin binding site, which allows the myosin to pull the actin filament towards the center of the sarcomere.

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What is titin's role in muscle contraction?

Titin is a giant protein that acts as a spring, storing potential energy when a muscle is stretched and releasing it during contraction, contributing to the force of the contraction. It also acts as a scaffold for myosin filaments and helps prevent overstretching of the sarcomere.

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What is the role of antagonist muscles?

Antagonist muscles work in pairs. When one muscle contracts, its antagonist relaxes, allowing the relaxed muscle to lengthen. The contracting muscle provides the energy needed to lengthen the relaxed muscle.

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Study Notes

Movement in Organisms

  • Movement is a vital life function, with adaptations varying across organisms.
  • Internal movements occur within organisms, such as peristalsis in the gut and ventilation in lungs.
  • Motile organisms move their entire body, from one place to another, a process called locomotion.
  • Sessile organisms stay in one place (e.g., plants rooted in soil, corals).

Muscle Contraction

  • Muscle fibers contain many parallel, cylindrical myofibrils.
  • Each myofibril has repeating units called sarcomeres.
  • Sarcomeres consist of overlapping actin and myosin filaments.
  • Myosin filaments contain "heads" that bind to actin, creating cross-bridges.
  • The cross-bridges cause the actin filaments to slide past the myosin, shortening the sarcomere and thus the muscle.
  • The interaction of many myosin heads amplifies the force exerted by the muscle.
  • Dark bands contain myosin, light bands actin.
  • Z-lines define boundaries of sarcomeres.

Muscle Relaxation

  • Titin, an elastic protein, stores potential energy during muscle relaxation, contributing to muscle contracting force.
  • Titin connects myosin filaments to Z-discs.
  • Energy is needed to stretch titin and lengthen a muscle.
  • Another muscle (antagonist) provides energy to lengthen the relaxed muscle.

Motor Units

  • Skeletal muscles are composed of striated muscle fibers.
  • A motor unit is a motor neuron and all the muscle fibers it stimulates.
  • Simultaneous contraction in a muscle group is possible through this pattern.

Skeletons for Movement

  • Skeletons provide support and protection for animals.
  • Exoskeletons (e.g., arthropods) are external, while endoskeletons (e.g., vertebrates) are internal.
  • Skeletons act as levers to change the size and direction of forces.
  • Muscles are attached to bones at insertion and origin points.
  • Levers increase speed, force, or both to maximize movement.

Synovial Joints

  • Synovial joints allow articulation, or movement, of bones.
  • They have components like bones, ligaments, cartilage, and synovial fluid.
  • Cartilage covers bones, providing smooth surfaces to reduce friction.
  • Synovial fluid lubricates the joint and cushions against shocks.
  • The joint capsule encloses the joint, preventing dislocation.

Measuring Range of Motion

  • Range of motion is measured using tools like goniometers.
  • Computer analysis also helps with measuring movement.

Importance of Locomotion

  • Animals move for various reasons, including foraging for food, searching for mates, escaping dangers and migration.
  • Examples of different animals and behaviours are provided.

Intercostal Muscles

  • Intercostal muscles are involved in breathing.
  • External intercostals contract to increase thoracic volume during inhalation.
  • Internal intercostals contract to decrease thoracic volume during exhalation.

Marine Mammal Adaptations for Swimming

  • Water is denser and more viscous compared to air.
  • Streamlining is crucial for reducing water resistance (e.g. body shape, flippers, flukes).
  • Blubber provides buoyancy and reduces friction.
  • Adaptations for periodic breathing are present to allow dives and quick re-emergence (e.g., blowhole, smooth muscle in airways).

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B3.3 Muscle and Motility PDF

Description

Explore the essential concepts of movement in organisms, including internal and locomotion. Delve into the mechanics of muscle contraction, focusing on the structure of myofibrils, sarcomeres, and the interaction of actin and myosin. Understand how these components work together to facilitate movement and muscle function.

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